This invention is related to a programmable system for controlling a plurality of electrical loads, more particularly, to a programmable system controller for accepting switch and telephone commands and providing in response thereto drive signals for controlling one or more output devices such as banks of relays.
The means for selecting the required response of the programmable system controller are typically in the form of switches that may be manually or automatically operated. For certain applications it is advantageous that the programmable system controller have the capability to respond to commands initiated by a telephone. The telephone commands are in the form of electrical quantities having a value determined by the selection of the push buttons of the telephone. The switches along with the telephone commands provide the stimuli for the dynamic operation of the programmable system controller.
The switches may be of a two-wire maintained switch, commonly known as a single pole, single throw (SPST) switch, a three-wire maintained switch, commonly known as a single pole, double throw (SPDT) switch, or a momentary switch comprised of two push buttons and commonly in the form of two single pole, single throw, momentary action switches. The programmable system controller must be able to correctly respond to these various types of switches. For those applications related to interfacing with a telephone, the programmable system controller must be able to respond to the electrical signals generated the manual operation of the telephone and notify or direct the correct sequential operation of the telephone.
The selectable switches sometimes in cooperation with the telephone commands commonly determine the mode of operation of the programmable controller so as to sequentially operate one or more banks of relays, which, in turn, determine the operation or state of remote devices. The switches along with the telephone commands may select the operation of Bank A and Bank B relays, Bank A relays or Bank B relays.
The automatic or manual operation of the switches may allow or cause multiple switch input commands to be sent and received by the programmable controller without allowing for ample time for the programmable controller's response. The programmable controller must be able to decide which of the multiple switch inputs received should be ignored and which ones should be responded to in order to assure the correct operation within the limitation of the programmable controller's response time. Further, it is desired that the programmable controller be able to make this determination even though it is unaware of what type of various switches is generating the switch command so as to properly activate the desired, commanded, Bank(s) of relays.
The telephone commands initiated by the manual operation of the telephone having a variable duration must be responded to or ignored by the programmable controller within a predetermined duration so the programmable controller may also be able to perform other tasks. Further, the programmable controller must be able to lead or direct the manual operation of telephone to allow the operator to perform the desired operation within the predetermined duration established by the controller.
Prior art programmable controller typically set a fixed method or process to respond to the switch input commands. For example, some prior art programmable controller respond to the first switch input command which is received and ignores any other switch commands during its processing of the first input command. Still further, other programmable controllers set a fixed duration for detecting the occurrence of switch input command so as to only respond to the first and last input switch commands received during the fixed input duration. In addition, with regard to responding to various type of switches generating the input switch commands, the types of switches used to generate the switch input command are hard wired and have a fixed location, time wise, in any transmission of the input switch commands so that the programmable controller has prior knowledge of each type of switch as to it being a two-wire maintained, a three-wire maintained or a momentary switch.
It is an object of the present invention to allow the user or the person selecting the type of switch, which generates the related switch commands, to be given the flexibility to establish the functionality of each switch as being a two-wire maintained, a three-wire maintained or a momentary switch and thereby place the burden to determine the type of switch being used on the programmable controller that is responding to the selected switch command. If such is accomplished, it permits the user of the programmable controller to remotely control electrical loads by means of various types of select switches that may be all placed on a single device such as a control panel and significantly ease the limitations put on the product by eliminating switch-type constraints.
Further, it is an object of the present invention to allow for an increased variation of component tolerances of the switches together with the associated circuit components that interface with these switches. Specifically, it is desired to increase the variation of component tolerances related to the switches themselves and also to allow for increased variations of the resistors and capacitors typically used to interface with the switches that provide a filtering function of the related switch commands which are transmitted to and received by the programmable controller. It is desired that the programmable controller provide means to compensate for the increased tolerances of all these devices while at the same time provide the desired response time to the received switch input commands.
Further still, it is an object of the present invention to provide a programmable controller that assures that when an input switch command is received without sufficient time to respond to successive received switch inputs, that the individual input actuations that do not effect the final output state be rejected and not acted upon by the programmable controller. In such an operation the programmable controller must selectively ignore the unnecessary received switch commands.
It is an object of the present invention to provide a programmable controller that responds to and directs the sequential manual operation of the telephone, in the form of electrical signals within a predetermined duration.
Still further it is an object of the present invention to provide a programmable controller having a sequential and predetermined operation that allows for a minimum output signal which is transmitted to relays controlling remote devices so that the maximum duty cycle of the relay is not exceeded, thereby, allowing for an increased reliability of the related drivers activating the relays.